Started in 1740, this third timekeeper took Harrison nearly 19 years to build
and adjust, although it was not to win him the great longitude prize: he found
that he just could not persuade the two large, heavy, circular balances to keep
time well enough. Nevertheless, H3 incorporates two extremely important
inventions, both relevant today: the bimetallic strip (still in use worldwide in
thermostats of all kinds) and the caged roller bearing, a device found in nearly
all modern mechanical engineering.
and adjust, although it was not to win him the great longitude prize: he found
that he just could not persuade the two large, heavy, circular balances to keep
time well enough. Nevertheless, H3 incorporates two extremely important
inventions, both relevant today: the bimetallic strip (still in use worldwide in
thermostats of all kinds) and the caged roller bearing, a device found in nearly
all modern mechanical engineering.
More on this interesting story, go to
http://www.nmm.ac.uk/harrison